Aaron Posted March 18, 2003 Share Posted March 18, 2003 Originally posted by No4 But at sea level you'll be dumping boost or needing a gate in the exhaust manifold to divert the exhaust gas from the turbo. If boost gets away on you and you can't match it with fuel flow, severe detonation occurs. Most of the turbo systems I've seen have either an integral wastegate in the turbine housing or have one installed elsewhere to control boost, are you saying that the aircraft systems you're used to don't? two words: Yii-Kes. Good points about detonation,etc. the Continental he's turbocharging is already a turbo model, runs a 7.5:1 compression ratio, and is set up for mild turbocharging (it looks like a pressure ratio of 1.1-1.5, based on engine HP). As I understand it the big thing for dust is getting rid of the 35 year old turbocharger and slapping in a new one, hopefully comparably sized. Do I have that right, dust? Dust, the other option you might consider is a turbo rebuild kit. That'll run you much less cash than a new turbo, get you good as new results, and would be much easier. Quote Link to comment Share on other sites More sharing options...
dust Posted March 18, 2003 Share Posted March 18, 2003 Until clifford started this post, that was my plan, but I've learned allot since then! What all this learning has done is given me options when i try to cram all of this under the cowl. If the one that is there is the best option, fine, if a newer one, as in brand new, would be a better option, well fine too, i now have more options and in this engine install thing, options is goot Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
LargePrime Posted March 18, 2003 Share Posted March 18, 2003 Dust; I havent finnished running the numbers on thoes turbos. I will get to it but the new buisness has me busy. I would like to note that 2 cars turbos would not have a problem at 120000 RPM. They regularly do 250000, sustained, like all other turbos. If a small car turbo with half the displacement can make 300 hp reliabily then it's not gonna have a problem with 100. So the idea that they would be "glowing Red" is just stupid. I should just get used to these moronic auto part prejudice. Quote We know who you are... Link to comment Share on other sites More sharing options...
dust Posted March 19, 2003 Share Posted March 19, 2003 well, i put this topic off a little and that was talking about a pre turboed engine, what clifford wanted to know was on adding a turbo to a stock lycoming 360. To be honest, it also interests me. I was thinking of buying one of the kits that are out there for a lycoming clone. And No4 reminded me of that. What say you, swap out the pistons for low compression pistons or could you just hold the boost down to ?? and leave the high compression pistons in? Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
John Slade Posted March 19, 2003 Share Posted March 19, 2003 Messing with a Lycoming seems like a bad idea to me, Mike. They're fragile enough as it is. If you're going to go to all the trouble of engineering something new and better, why not start with an engine that'll cost a lot less and is much more robust. Which engine am I talking about? I'll let you guess, but here's a hint. It doesnt have exhaust valves, pistons or piston rings. Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
LargePrime Posted March 19, 2003 Share Posted March 19, 2003 I would get a parts list of both the turbo and the non turbo and see if anything else is different. If it is only minor stuff (like the oil pan is different cause of an extra hole for drain back) then I would go with the lo compression pistons. the reason is detonation. Detionation is something you dont want anywhere near your engine. the turgo air will be much hotter than normal intake air, ofter 200F hotter. This really exagurates the possability of detonation. Truth is you could prolly get away with using the standard pistons. Chrysler guys did it all the time, since the engines were the same except for the pistons, but they could use really high quality gas reliabily (and use 104 boost), get a new motor for 1000$, and pullover if there was a problem. John Slade; When I slave with dust and clifford on there airplanes I wont talk about auto motive engines to him do to the allergic reacion he has. His eyes unfocus and he swelles visably. Of course he will say he just does not want to have a car engine in his aircraft, but the allergy is the real reason. And they do have piston rings. A functional equilivent anyway. In fact there seals are one of the weak points of the engine. But no valves!!! A turbochargers DREAM. As a semirelated random thought. I understand Greg Richter's turbo has no waste gate and no popoff valve. Assuming thats true and he somehow was able to engineer a way to do that, it would seem a great idea to find out how. Belay that. reread his page here and he has a 12 PSI Pop Off Valve. Oh well at least you could try to eliminate the waste gate, as Pop Off's are much lighter and simpler. John shame him into more pics of that engine. I really want to see that intake. Quote We know who you are... Link to comment Share on other sites More sharing options...
Aaron Posted March 20, 2003 Share Posted March 20, 2003 With all due respect to Richter and his efforts, I'm not sure I'd follow the same path (using a BOV and closing the wastegate) Heres why: 1)Your working the turbo harder than you need to. 2)No redundancy- if the BOV fails, overboost is likely and then detonation will occur. 3)because your compressing everything then blowing some off, the temperature of the charge is higher. 4)with no wastegate, all exhaust is forced through the turbine, creating turbo heat issues and making the engine less efficient (higher pressure drop in the exhaust section) For my design, an internal wastegate turbo will be used with the wastegate as the primary pressure regulator. A BOV set at max boost will also be used as a safety measure. Quote Link to comment Share on other sites More sharing options...
LargePrime Posted March 23, 2003 Share Posted March 23, 2003 A response... 1) The turbo is well matched to the application so an overboost would be an abnormal application. The BOV should be a saftey device only, in this application. Aaron would be correct in an automotivve application, again this aint one. 2) See above. The turbo is matched to the upper range of the engine, so overboost is rare. 3) Not if you blow off before you cool (before the intercooler). But this is a red herring as you wont be blowing off in a standard mode. 4) This statement assumes there is a heat issue with all the exhaust going thru the turbo. If so you got the wrong turbo. If not it's another red herring. I doubt if Greg's old engine used the BOV as part of the standard mode of application. If so it was a function of having such a large range of boost (1000-6500RPM). The Lyco wont have this. Quote We know who you are... Link to comment Share on other sites More sharing options...
Aaron Posted March 23, 2003 Share Posted March 23, 2003 All good points, LPrime. For what it's worth, the original tsio-360 turbo had a wastegate, according to dust. While it is possible to get the turbine perfectly matched, so that in closed loop it boosts to a particular pressure with no wastegate, I'm not familiar enough with the design calcs for that. Can you summarize the process, LPrime? How would you test this, considering you want a low pressure ratio at low altitude (~1.1) and a higher one (~1.5) at high altitude? Quote Link to comment Share on other sites More sharing options...
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